Abstract

Different SERS spectra of lysine (Lys) in Ag colloidal surface were obtained. No identical SERS spectra of Lys were observed after a stabilization period, suggesting that a unique conformation and orientation on the metal surface of lysine do not exist at neutral pH. In general, Lys molecules interact with the surface through both the carboxylate and amino groups; the aliphatic moiety is close to the surface. The interpretation of the experimental results is supported by theoretical analysis of the molecule on the silver surface. © 2008 Elsevier B.V. All rights reserved.